Prognostic value of the proliferation marker Ki-67 in laryngeal carcinoma : Results of the Accelerated Radiotherapy with Carbogen Breathing and Nicotinamide phase III randomized trial

Background The prognostic and predictive value of the proliferation marker Ki-67 was investigated in a randomized trial comparing accelerated radiotherapy with carbogen breathing and nicotinamide (ARCON) to accelerated radiotherapy in laryngeal carcinoma. Methods Labeling index of Ki-67 (Li Ki-67) in immunohistochemically stained biopsies and the colocalization with carbonic anhydrase IX (CAIX) were related to tumor control and patient survival. Results On average, node-positive patients had a higher Li Ki-67 (median 14% vs 8%; p < .01). In patients with a high Li Ki-67, the 5-year regional control and metastases-free survival were 79% versus 96% (p < .01) and 71% versus 88% (p = .05) for accelerated radiotherapy and ARCON, respectively. The 5-year local control and disease-specific survival were not significantly different. Patients with low Ki-67 expression had an excellent outcome with accelerated radiotherapy alone. Conclusion Patients with laryngeal carcinomas with high proliferative activity are at increased risk of regional and distant metastases formation. This risk can be reduced by treatment with ARCON